<html>

<head>
  <title></title>

</head>

<body>
  <style>
    div span {
      background-color: aqua;
      height: 300px;
      width: 100px;
      display: inline-block;
    }

    @media screen and (max-width: 600px) {
      div span {
        background-color: blue;
      }
    }

    div {
      background-color: brown;
      width: 400px;
      margin: 0 auto;
    }
  </style>
  <div>
    <span>test</span>
  </div>

</body>

</html>